Opening and locking from the inner side - SmartIntego Locking cylinder (Z4)

With freely rotating locking cylinders (FD)

The outer and inside thumb-turn rotate freely when not activated in the freely rotating SI-Locking Cylinder, Doors can also only be opened or locked on the outside using an ID medium on the inside thumb-turn.

With non-freely rotating locking cylinders (CO)

SI-Locking Cylinders which are permanently engaged for use can be operated from the inside without a ID medium. In this case, the door can be opened and closed using the inside thumb-turn without an authorised ID medium.